Seed 412

Every generated image has a number attached to it, usually somewhere you don't look. It's called the seed, and it's the plainest thing in the settings: a whole number, sometimes nine or ten digits long, often left on random so that it changes every time you press the button. The lotus at the top of this page has the seed 412.

The seed decides the static. Before the model can take any noise away, something has to make the noise, and computers don't produce randomness so much as recite it. A generator takes a starting number and unrolls it into a long sequence that looks random and isn't. Give it 412 and it lays down the same grey field every time, down to the last speck. So the seed isn't really a property of the picture. It's the exact patch of static the picture was carved out of.

That sounds like a technicality until you use it. Keep the seed fixed, along with the model, the size and the sampler, and you get the same image back. Not a similar one: the same one, or close enough that you'd need software to find the difference. Which means you can leave. You can close everything, come back another day, type 412 and stand in the same spot.

The more interesting thing is what happens when you change one word. Same seed, same settings, and lotus becomes lily. Most of the time, most of the picture stays where it was. The flower stays in the middle and the loose shards still drift in from the corners. What changes is what the shapes agreed to be.

That's because the broad layout of an image is settled early, in the first handful of steps, when there's still far more noise than picture and the static has a lot of say. Where the noise happens to be a little brighter, the model tends to put something bright. The prompt steers, but it steers a car that's already moving. Change one word and you take a slightly different road through the same country.

It doesn't always hold. Swap the flower for a staircase and the place rearranges itself completely, the way a room does when you move the one piece of furniture everything else was arranged around. Change the size of the image and the static changes shape with it, so there's no 412 to go back to, only a new patch under the old name. A seed is a fixed point only while everything around it stays fixed too.

The eclipse at the top of another essay on this site is also seed 412. Strictly, it isn't the same static, because that picture is wide and this one is square. Two places that happen to share a name, and nothing else I can find.

Here's the part I like best. The numbers aren't arranged by distance. Seed 413 isn't next door to 412. It isn't slightly different static; it's entirely different static, as unrelated as two pages opened at random in a long book. There's no walking from one to the next, and no point looking for a lucky neighbourhood. Every number is somewhere else.

So I've stopped thinking of seeds as random. Random is only what a seed is when you first meet it. Once you've found one that holds a picture well, it becomes an address, and I keep a short list of them the way you might keep a list of spots where the light is good at a certain hour. Some like to put the bright thing in the middle. Some leave a lot of dark at the top, which is useful if you want a sky.

None of this is real in any deep sense. It's the habit of one patch of noise under one model, and it won't survive a change of either. A new model reads the same static differently, the way a new tenant hangs different pictures in the same rooms. But it's real enough to be useful, the way a favourite chair is.

There's nothing special about the number itself. I typed it once without thinking, and the picture that came back was good enough that I typed it again. That's all it took. A seed means something only because you keep returning to it, and the static has no idea. It doesn't remember me. I'm the one who remembers it.